I have actually spoken with Litz about this very topic. Of course he said it comes down to BC for long range, and that the tighter twist is really best suited for much heavier rounds like this one that he designed:
http://www.buyabmammo.com/308-winchester-185gr-berger-match-juggernaut-target.html

.308AR barrel with a 1:8 twist? You'll probably have to go custom. I've only seen that on a couple shorter barreled R700's and custom guns. Never seen a factory barrel on an AR in .308 with that twist. What length are you looking for, and why such a tight twist? You planning on using super-heavy bullets?

Yeah, APA and PA use steeper baffle angles, but somehow MBM is able to get equal or better results with his specific shape and angle. Of course, his best results at recoil reduction were brakes on larger calibers with 4 or 5 ports.

Let us know what you find! They were both tested, but in two separate tests. Based on comparing brakes that were similar in both tests, the MBM should be superior (and probably louder!). Also, the design of the M4-72 would work better if the larger baffle was the first port closest to the muzzle. The way it is now, the first two do most of the work.

Yes, I got my Surefires second hand as well. Great deals on EBay. One lasted for years, and when it went finally went down (older model, lots of use an abuse), Surefire replaced it with the current upgraded model, no questions asked. Amazing customer service.
Streamlight is a good value, but not build as heavy duty (there are entire articles comparing them in detail), and most importantly more me, the toggle butterfly switch is uni-directional. Only one direction is used for constant on and other other for momentary. Personally, I find the complete ambi set up of Surefire a lot more user friendly, intuitive and better for stressful situations.
I borrowed my friend's Viridian and ran it for a couple days. While the green laser is super bright, the adjustments were horrible, build was very flimsy, and I seriously doubt it would survive one accidental or intentional knock against a barricade or drop on the deck. I would definitely hesitate to bet my life on it
my $0.02

I Totally agree with 98Z5V. The activation method that best suits your preferred grip will likely dictate the best position. I run a sure X200 on my Glock, and use a "C-clamp" type grip on my AR forend with the index finger extended straight towards the target. So, using my support hand thumb to sweep the butterfly switch of the X300 is almost identical to sweeping it when holding my Glock. Plus, as 98Z5V wrote, in the 12 or 6 o'clock position it's ambi if you need to switch sides.